ES2926665T3 - Polymer composition comprising a polyethylene - Google Patents

Abstract

The invention relates to a polymer composition comprising a polyethylene and a crosslinking agent, wherein the polymer composition contains a total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms, and B1<=B, where B1 is 0.88, when measured before crosslinking according to ASTM D624898 method; and wherein the crosslinking agent is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymer composition, and Z <= Z2, where Z2 is 0.60 an article being, for example, a cable, for example a power cable and processes for producing a polymeric composition and an article; useful in different end applications such as wire and cable (W&C) applications. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Polymeric composition comprising a polyethylene

field of invention

The invention relates to a polymeric composition comprising a polyethylene and a crosslinking agent, an article comprising a layer or layers, for example insulating layer(s) obtained from the polymeric composition, the The article can be a cable, for example a power cable, processes for producing the polymer composition and the article comprising the use of a polymer composition. In addition, the polymeric composition can be useful in different end applications, such as wire and cable (W&C) applications, especially in cable applications, such as power cable applications, for example, in medium voltage (MV) and, for example, , in high voltage (HV) and, for example, extra high voltage (EHV) cable applications. Furthermore, the polymeric composition may be useful in both alternating current (AC) and direct current (DC) applications.

prior art

Polyethylenes produced in a high pressure (HP) process are widely used in demanding polymer applications where the polymers must meet high mechanical and/or electrical requirements. For example, in W&C applications, for example, power cable applications, for example, in low voltage (LV), MV, HV, and EHV applications, the mechanical and electrical properties of polyethylenes, and of the polymer compositions that comprise polyethylenes, are of significant importance.

For example, in power cable applications, particularly in MV and especially in HV and EHV cable applications, the electrical properties of the polymer composition are of significant importance. Also, the electrical properties, which are important, can differ in different cable applications, as is the case between AC and DC cable applications.

In addition, crosslinking of polymers, eg, polyethylenes, is also known to contribute substantially to improved heat and deformation resistance, mechanical strength, chemical resistance, and abrasion resistance of a polymer. Therefore, crosslinked polymers are widely used in different end applications, such as the mentioned W&C applications.

Also, in cable applications, an electrical conductor is typically coated with an inner semiconductive layer first, followed by an insulating layer and an outer semiconductive layer. To those layers, additional layers can be added, such as screens and/or auxiliary barrier layers, for example one or more water barrier layers and one or more skin layers.

Due to the benefits mentioned herein that can be achieved with crosslinking, insulating layer and semiconductive layers in cable applications are typically made using crosslinkable polymeric compositions. The polymeric compositions are then crosslinked in a layered cable application.

Furthermore, such crosslinkable polymeric compositions comprising low density polyethylene (LDPE) are among the predominant cable insulation materials for power cables today.

Crosslinking can be done with crosslinking agents where the crosslinking agents decompose generating free radicals. Such crosslinking agents, eg peroxides, are conventionally added to the polymeric material before or during extrusion of the cable. Preferably said crosslinking agent should remain stable during the extrusion step. The extrusion step should preferably be performed at a temperature low enough to minimize early decomposition of the crosslinking agent, but high enough to obtain adequate melting and homogenization of the polymer composition. If a significant amount of the cross-linking agent, e.g. peroxide, already breaks down in the extruder and thus initiates premature cross-linking, it will result in the formation of what is known as "burn", i.e. lack of homogeneity, surface irregularities and possibly discoloration in the different layers of the resulting cable. Therefore, any significant decomposition of cross-linking agents, ie free radical forming agents, must be avoided during extrusion. Instead, crosslinking agents should ideally simply be decomposed in a subsequent elevated temperature crosslinking step. The elevated temperature will increase the rate of decomposition of the crosslinking agents and thus increase the rate of crosslinking, and a desired, ie, target, degree of crosslinking can be achieved more quickly.

Furthermore, when a polymeric composition is crosslinked, for example in a cable, the decomposition of crosslinking agents, eg peroxides, during crosslinking will also result in the formation of peroxide decomposition products. Some of the peroxide decomposition products are volatile and their main component is methane if the types of peroxides normally used for cross-linking are used, for example with a cable. The peroxide decomposition products mostly remain captured within the polymer composition, eg, of a cable, after crosslinking. This causes, for example, problems both in the cable manufacturing process and in the quality of the final cable.

Especially MV, HV, and EHV power cables must have high-quality coatings to aid safety during installation and in the end uses of such cables. In the facility, for example, it is important to prevent captured decomposition products, for example flammable methane, from igniting, for example, when end caps are removed. In service, volatile peroxide decomposition products formed in a cable during a crosslinking step can create gas pressure and thus cause defects in the shield and joints. For example, when the center of a cable is equipped with a metal barrier, gaseous products can exert pressure, especially at the joints and terminations, thus causing a system failure. Therefore, it is necessary to reduce the level of these volatile peroxide decomposition products to a sufficiently low level before subsequent steps of cable production can occur.

A sufficiently low level of volatile peroxide decomposition products makes the use of the polymer composition, comprising LDPE, safe for use in installations, such as cable installations, and with accessories, such as cable accessories. Therefore, nowadays in the cable production process a degassing step is necessary, which reduces the level of volatile peroxide decomposition products. The degassing step is a time and energy consuming and therefore costly operation in a cable manufacturing process. Degassing requires large heated chambers that must be well ventilated to prevent buildup of, for example, flammable methane. The core of the cable, i.e. the layers and the conductor, usually wound on cable drums, is normally kept in said degassing step at elevated temperature in the range of 50-80 °C, for example 60-70 °C. C, for long periods of time. When exposed to the required temperatures, thermal expansion and softening of the insulation can occur and lead to unwanted deformation of the cable layers formed, directly resulting in cable failure. Therefore, degassing of HV and EHV cables with high cable weight must often be carried out at lower temperatures, further prolonging the degassing time. Therefore, there is a need to find new solutions to overcome the problems of the state of the art.

In addition, the crosslinking of a polymeric composition comprised, for example, in a cable contributes substantially to improving the resistance to heat and deformation, the mechanical capacity, the chemical resistance and the resistance to abrasion of the polymeric composition and the cable that comprises the composition. polymeric.

In this context, see document US5539075 which relates to a method for producing an unsaturated copolymer of ethylene and at least one monomer, wherein the monomer is a polyunsaturated compound copolymerizable with ethylene.

See also EP2318210B1, which relates to a polymer composition comprising an ethylene unsaturated LDPE copolymer with one or more polyunsaturated comonomers and which is suitable for crosslinked polymer applications. The polymer composition has a melt flow index under 2.16 kg load, MFR2, of at least 2.8 g/10 min, and contains carbon-carbon double bonds in an amount of at least 0.40 double bonds carbon-carbon/1000 carbon atoms.

Furthermore, different materials, ie, polymer compositions, may be needed for different cables, cable constructions, and lines. Furthermore, it is not possible to lay all cables or cable constructions on all cable lines using standard viscosity "cross-linked" (herein more accurately means "cross-linkable") polyethylene (XLPE) materials with a flow rate of melting under a load of 2.16 kg, MFR2, values of about 2 g/10 min. This is because those standard viscosity XLPE materials do not have sufficient soften mold strength. The insufficiency in the resistance to molding by softening is usually solved, in the case of a cable, by using materials with MFR2 values lower than 2 g/10 min. Materials having MFR2 values less than 2 g/10 min have high viscosity and better soften mold resistance. Improved soften molding resistance is necessary for large cable constructions and for cable production on catenary cable lines, as well as for cable production on horizontal cable lines. For example, in horizontal continuous vulcanizing lines, for example a Mitsubishi Dainichi continuous vulcanizing (MDCV) line, and in catenary continuous vulcanizing (CCV) lines (especially for thicker constructions) to produce cables, the use of of polymeric materials, e.g. for insulation layers, which have a lower MFR2 compared to the MFR2 of polymeric materials (e.g. standard viscosity XLPE materials) used in vertical continuous vulcanization (VCV) lines and CCV lines (for slimmer builds).

In horizontal continuous vulcanizing lines to produce cables, the conductor may sag within the insulation layer, if polymeric materials having too high MFR ² are used, the sag of the conductor may also result in eccentricity of the center of the cable.

Also, in CCV lines, if polymeric materials are used that have too high MFR2, i.e. also have too low soften molding resistance, the wall thickness may become too large since the soft melt polymeric material of an insulation layer can fall off the conductor. That would result in a downward displacement of the insulation layer, which will generate an eccentricity, for example, the so-called pear-shaped center of the cable.

In addition, insufficient softening mold strength can be counteracted by different methods, such as:

use of eccentric tools in the extruder head to compensate for the sinking effect of the conductor; torsion of the center of the cable to counteract the displacement of the conductor,

use of a double rotation technique to counteract the pear shape and also the use of an inlet heat treatment (EHT).

Consequently, polymeric materials having a comparatively lower MFR2 and higher viscosity, as already described, are typically used to counteract such soften molding behaviors.

However, materials that have a high viscosity will generate a higher melt temperature under commonly used extrusion conditions, which can lead to a higher risk of premature crosslinking and thus formation of prematurely crosslinked matter, i.e. , "Burned". "Burning" can be, as already described herein, inhomogeneities, surface irregularities and/or possibly discoloration in the different layers of, for example, the resulting cable. The formation of "burn-in" can have a severe impact on the productivity of cable lines, as it greatly limits the length of production before cleaning is necessary, thereby reducing the production rate. Therefore, when producing a cable, by using polymeric materials that have a lower MFR2 that generates a higher temperature in the melt, a lower production speed is required to reduce the melt temperature and therefore minimize "burn-in".

Therefore, a drawback to lowering the MFR2 value of a material may be that it also requires changes in processing conditions, such as lowering the production rate.

Processing conditions, in addition to soften mold resistance, are also properties that are important in connection with crosslinkable XLPE materials, such as peroxide crosslinkable XLPE materials. Ideally, the material should have a low viscosity in the extrusion step of the process in order to have a desirably low melt temperature in the extrusion step. On the other hand, a comparably higher material viscosity may be desirable in the crosslinking step of the process. If a crosslinkable XLPE material generates a low melting temperature, there is less risk of "burn" formation during extrusion, for example, of a cable construction, compared to an extrusion involving another crosslinkable XLPE material which generates a low melting temperature. highest melting temperature.

Both soften mold strength and viscosity at processing conditions can be visualized by viscosity curves obtained from plate-to-plate rheology measurements. Therefore, said softening mold strength is visualized through the complex viscosity (r|*) at very low shear rates, i.e., r|* 0 and n* 0.05 at 0 rad/sec and 0, 05 rad/sec, respectively, and said viscosity under processing conditions is then visualized through the complex viscosity n* 300 at 300 rad/sec. Yet another important property for XLPE is degree of crosslinking where the target degree of crosslinking level should be achieved, ideally with as little crosslinking agent as possible, such as peroxide. The degree of crosslinking can be measured, for example, with a so-called hot fit test. According to said hot set test, the lower the hot set elongation value, the more crosslinked the material. As little crosslinking agent as possible reduces volatile peroxide decomposition products and also reduces the time required for degassing.

The extrusion and crosslinking steps of a polymeric material included, for example, in the production of cables have different requirements. The critical parameter for the extrusion step is, as already described, that the polymeric material generates a low melt temperature to reduce the risk of "burns". This is influenced by the rheological properties in the shear rate region that the polymeric material exhibits in the extruder, eg using a low complex viscosity (n*) at 300 rad/sec. A low complex viscosity (n*) at 300 rad/sec is generally associated with a polymeric material having a higher melt flow rate (MFR2).

However, an increase in melt flow index often needs to be balanced as a polymeric material with a high MFR2 has too low a soften molding resistance that will result in, for example, a non-centric cable, which is not acceptable. The rheological property influencing soften mold strength is complex viscosity (r|*) at very low shear rates, eg, at 0 rad/sec. However, the complex viscosity (r|*) at 0 rad/sec is an extrapolated value and therefore a measured complex viscosity (r|*) at 0.05 rad/sec is used here instead.

Therefore, there is a need to find new solutions to overcome the problems of the state of the art.

Description of the invention

The present invention relates to a polymeric composition comprising a polyethylene and a crosslinking agent, wherein the polymeric composition contains a total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms, and Bi < B, where Bi is 0.88, when measured before crosslinking according to ASTM method D6248-98; and the crosslinking agent is present in an amount that is Z wt%, based on the total amount (100 wt%) of the polymer composition, and Z < Z2, where Z2 is 0.60.

In one embodiment, the inventors have discovered that the combination of the aforementioned characteristics with a relatively low MFR2 surprisingly leads to a polymer composition with attractive properties, as discussed below.

The polymer composition according to the present invention, which contains the comparatively highest total amount of vinyl groups, B, as defined herein, surprisingly combines in one polymer composition:

good processability, e.g. good flowability, which is generally only associated with materials having a comparably higher MFR2, with excellent soften mold strength generally only associated with materials having a comparatively lower MFR2, and exhibits methane levels surprisingly low, and a technically desirable level of degree of crosslinking is maintained.

Furthermore, the polymer composition combines excellent soften mold resistance with good processability, eg flowability, also illustrated by the fact that the polymer composition exhibits balanced complex viscosities (r|*) at 300 rad/sec and at 0, 05 rad/sec, both complex viscosities (r|*) are determined before crosslinking according to the ISO 6721-1 method on stabilized polyethylene samples. The complex viscosity (r|*) at 300 rad/sec is therefore low, and the complex viscosity (r|*) at 0.05 rad/sec is therefore high, resulting in a polymeric composition, according to the present invention, which has improved processing properties in an extruder, and which still allows the generation of a cable, including large cable constructions, with good centricity in the production of cables for all types of cable lines. In this way, such cables can be produced, comprising layers, for example of insulation, obtained from the polymer composition.

Furthermore, the polymer composition according to the present invention has also unexpectedly been shown to exhibit surprisingly low levels of methane, while at the same time maintaining a technically desirable level of degree of crosslinking of the polymer composition by using a relatively low amount of the methane. crosslinking agent, ie, Z wt%, as defined herein. The technically desirable level of degree of crosslinking ensures sufficient thermomechanical properties, eg maintaining dimensional stability at elevated temperature. The crosslinking agent can be, for example, peroxides which are well known in the art. The amount of volatile decomposition products formed, where the main component is usually methane, is directly dependent on the amount of crosslinking agent, eg peroxide, that is added to the polymer composition. For any given crosslinking agent, eg peroxide, the amount of volatile decomposition products formed also depends on the chemical structure of the crosslinking agent. Furthermore, selecting such a relatively low amount of the crosslinking agent, while maintaining the desirable level of degree of crosslinking of a polymer composition, enables a polymer composition that exhibits low levels of methane and retains a memory effect when crosslinked.

Such low levels of methane allow for a shorter degassing time or alternatively make the degassing step completely redundant, both alternatives being highly beneficial for the general production of crosslinked and crosslinkable articles, for example cables, comprising layer(s). , for instance. an insulating layer, obtained from the polymeric composition.

Therefore, the polymeric composition comprising the polyethylene of the present invention is clearly highly advantageous for use in the production of crosslinkable and crosslinked articles, eg cables, eg layers of cables thereof, eg layers cable insulation.

The polymeric composition is crosslinkable and is well suited for the production of crosslinkable articles, eg one or more crosslinkable layers of a cable, eg one or more crosslinkable insulating layers of a cable, which layers are subsequently crosslinked.

"Crosslinkable" is a well-known expression and means that the polymer composition can be crosslinked, for example, through the formation of radicals, to form bridges, among others, between the polymer chains. The polymeric composition comprises a polyethylene and a crosslinking agent.

Polyethylene will be described in detail in the "Polyethylene of the Polymer Composition" section.

The polyethylene comprised in the polymeric composition of the present invention may be unsaturated or saturated. Another embodiment of the present invention is provided wherein the polyethylene is saturated.

Note that the terms "embodiment" or "embodiments", even if they stand alone herein, always refer to the embodiment of the present invention or embodiments of the present invention.

In another embodiment, a polymer composition of the present invention is provided comprising a polyethylene, wherein the polyethylene is unsaturated.

That the polyethylene is "unsaturated" means herein that the polyethylene comprises carbon-carbon double bonds. Carbon-carbon double bonds mean unsaturation herein. Polyethylene, as described herein, comprises vinyl groups, eg, allyl groups. Vinyl groups are functional groups that comprise carbon-carbon double bonds. The term "vinyl group" as used herein has a conventional meaning, ie, the moiety "-CH=CH ² ". Furthermore, the polyethylene may further comprise other functional groups which also comprise carbon-carbon double bonds. The other functional groups, which also comprise carbon-carbon double bonds, can be, for example, vinylidene groups and/or vinylene groups. The vinylene group has a cis or trans configuration. For the avoidance of doubt, vinylidene groups and vinylene groups are not vinyl groups as those terms are used herein.

Said "total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms" means the "total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms" present in the polymer composition when measured before crosslinking according to the present invention. Furthermore, at least the polyethylene contains such vinyl groups which contribute to the total amount of vinyl groups.

The polymer composition may optionally comprise other vinyl group-containing component(s), which then also contribute to the total amount of said vinyl groups. Therefore, in one embodiment, the vinyl group content is measured in the polymer composition as a whole and not only in the polyethylene thereof.

The ASTM D6248-98 method for determining the amount of vinyl groups is described in "Determination Methods." Still another embodiment of the polymer composition according to the present invention, as described herein, discloses a polymer composition, wherein the polymer composition contains a total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms, and Bi < B, where Bi is 0.89, when measured prior to crosslinking according to ASTM method D6248-98.

Still another embodiment of the polymer composition is disclosed, wherein Bi is 0.90.

In another embodiment according to the present invention, a polymer composition is disclosed, as described herein, wherein Bi is 0.92.

Another embodiment of the polymer composition is further disclosed, wherein Bi is 0.94.

Still another embodiment of the polymer composition is disclosed, wherein Bi is 0.95.

Another embodiment of the polymeric composition is further disclosed, wherein Bi is i.00.

Additional embodiments of the polymer composition are disclosed, where Bi is 0.95, i.00, i.05 or i, i0.

Still other embodiments of the polymeric composition are disclosed, wherein Bi is 0.90, 0.95, i.00, i .05, i, i0 , i, i5 , i.20, i.25 or i.30.

Additional embodiments of the polymer composition are disclosed, wherein Bi is 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, or 1.30, and /or Z2 is 0.48 or 0.46.

Still further embodiments of the polymer composition are disclosed, where B1 is 1.15, 1.20, 1.25 or 1.30. Still another embodiment of the polymer composition is disclosed, wherein B1 is 1.30.

Still a further embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein B < B2 and B2 is 3.0.

Additional embodiments of the polymer composition are disclosed wherein the polymer composition contains a total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms, and B1 < B < B2, wherein B1 and B2 may each be selected from any of the values given herein for B1 and B2, respectively. Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein B2 is 2.5.

In a particularly preferred embodiment B1 is 0.89 and B2 is 3.0, even more preferably B1 is 0.90 and B2 is 1.5.

The polymeric composition further comprises a crosslinking agent.

The crosslinking agent, for example a peroxide, is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymer composition, and Z < Z2, where Z2 is 0, 60.

In another embodiment according to the present invention, the polymeric composition, as described herein, wherein the crosslinking agent is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymer composition, and Z1 < Z, where Z1 is 0.01.

Crosslinking agent is defined herein as any compound capable of generating radicals that can initiate a crosslinking reaction. For example, the crosslinking agent contains an -O-O- bond.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein the crosslinking agent comprises peroxide, eg, a peroxide.

In another embodiment, the crosslinking agent comprises peroxide, ie, it comprises at least one peroxide unit per molecule of crosslinking agent.

In yet another embodiment, the crosslinking agent comprises a peroxide.

In another embodiment, the crosslinking agent is a peroxide.

In further embodiments of the present invention, a polymer composition is disclosed, as described herein, wherein Z1 is 0.02, 0.04, 0.06, or 0.08.

Furthermore, embodiments of the polymer composition according to the present invention are disclosed, as described herein, wherein Z1 is, for example, 0.1 or 0.2 and/or Z2 is, for example, 0.58 or 0. .56.

In another embodiment Z2 is 0.58 or 0.56. In yet another embodiment Z2 is 0.58. Also in another embodiment Z2 is 0.56. In another embodiment, Z2 is 0.54, 0.52, or 0.50. In yet another embodiment Z2 is 0.54. Also in another embodiment Z2 is 0.52. In another embodiment, Z2 is 0.50.

In another embodiment Z2 is 0.48 or 0.46. In yet another embodiment Z2 is 0.48. Also in another embodiment Z2 is 0.46. Another embodiment of the polymeric composition according to the present invention is disclosed, as described herein, the amount Z of the cross-linking agent, eg a peroxide, Z2 being 0.45.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Z2 is 0.44 or 0.42.

In yet another embodiment, the amount Z of the crosslinking agent, eg, a peroxide, is Z2 being 0.40. Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Z ² is 0.38 or 0.36.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Z ² is 0.38.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Z2 is 0.36.

In yet a further embodiment, the amount Z of the crosslinking agent, eg, a peroxide, is Z2 being 0.35.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Z2 is 0.34, 0.32 or 0.30.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Z2 is 0.34.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Z2 is 0.32.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Z2 is 0.30.

Non-limiting examples of cross-linking agents include organic peroxides, such as di-tert-butylperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-di(tert-butylperoxy)- 2,5-dimethylhexane, tert-butylcumylperoxide, di(tert-butylperoxide), dicumylperoxide, butyl-4,4-bis(tert-butylperoxy)-valerate, i,i-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, peroxybenzoate tert-butyl, dibenzoyl peroxide, bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1,1-di(tert-butylperoxy)cyclohexane, 1,1-di(tert-butylperoxy) )cyclohexane, or any mixture thereof.

In further embodiments, the peroxide crosslinking agent can, for example, be selected from 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-di(tert-butylperoxy)- 2,5-dimethylhexane, di(tert-butylperoxyisopropyl)benzene, dicumylperoxide, tert-butylcumylperoxide, di(tert-butyl)peroxide, or any mixture thereof.

In yet another embodiment, the crosslinking agent is a peroxide selected from any dicumylperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, and tert-butylcumylperoxide, or any mixture thereof.

In another embodiment, the crosslinking agent comprises a peroxide that is dicumylperoxide.

In yet another embodiment, the crosslinking agent comprises a peroxide that is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3.

In yet another embodiment, the crosslinking agent comprises a peroxide that is tert-butylcumylperoxide. In one embodiment, the polymer composition comprises the crosslinking agent.

Still a further embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein B < B2 and B2 is 3.0 and Zi < Z < Z2, where Zi is 0.01.

Additional embodiments of the polymer composition, as described herein, are disclosed, wherein the crosslinking agent is present in an amount that is Z wt%, based on the total amount (100 wt%) of the polymer composition. , and Zi < Z < Z2, where Zi and Z2 may each be selected from any of the values given herein for Zi and Z2, respectively.

In another embodiment according to the present invention, as described herein, Zi is 0.05.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Zi is 0.i0.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Z2 is 0.i5.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Z ² is 0.20.

In a particularly preferred embodiment Zi is 0.15 and Z2 is 0.60, even more preferably Zi is 0.25 and Z2 is 0.50.

The MFR2 is determined, before crosslinking, according to ISO 1133-1:2011 under a load of 2.16 kg and at 190 °C.

In a further embodiment according to the present invention, the polymeric composition, as described herein, before crosslinking has a melt flow index (MFR2) at a load of 2.16 kg and at 190 °C, determined according to the ISO method 1133-1:2011, where MFR2 is A g/10 min and A < A2, where A2 is 10.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A2 is 5.0.

In yet another embodiment of the polymer composition, A2 is 4.0.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein A2 is 3.0.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A2 is 2.7.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A2 is 2.5.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein A2 is 2.0.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A2 is 1.7.

In yet another embodiment, the polymer composition has a melt flow index, MFR2, that is A g/10 min and A1 < A; where A1 is 0.05.

Additional embodiments of the polymer composition are disclosed having a melt flow index, MFR2, that is A g/10 min and A1 < A < A2; wherein A1 and A2 may each be selected from any of the values given herein for A1 and A2, respectively. Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein A1 is 0.10.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A1 is 0.15.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A1 is 0.20.

Further disclosed is an embodiment according to the present invention, as described herein, wherein A1 is 0.25.

A further embodiment according to the present invention is disclosed, as described herein, wherein A1 is 0.30.

An embodiment according to the present invention is disclosed, as described herein, wherein A1 is 0.35. Further disclosed is an embodiment according to the present invention, as described herein, wherein A1 is 0.40.

A further embodiment according to the present invention is disclosed, as described herein, wherein A1 is 0.45.

An embodiment according to the present invention is disclosed, as described herein, wherein A1 is 0.50. A further embodiment according to the present invention is disclosed, as described herein, wherein A1 is 0.55.

An embodiment according to the present invention is disclosed, as described herein, wherein A ¹ is 0.60.

An embodiment according to the present invention is further disclosed, as described herein, wherein Ai is 0.65.

A further embodiment according to the present invention is disclosed, as described herein, wherein A i is 0.70.

An embodiment according to the present invention is disclosed, as described herein, wherein Ai is 0.75.

An embodiment according to the present invention is further disclosed, as described herein, wherein Ai is 0.80.

A further embodiment according to the present invention is disclosed, as described herein, wherein A i is 0.85.

An embodiment according to the present invention is disclosed, as described herein, wherein Ai is 0.90.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A ² is i.65.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein A ² is i.60.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A ² is i.55.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein A ² is i.50.

In a particularly preferred embodiment, Ai is 0.i5 and ^A2 is 3.0, even more preferably Ai is 0.60 and ^A2 is

2.5.

In a preferred embodiment, the polymeric composition simultaneously complies with the following:

Bi < B < B ² where Bi is 0.89 and B ² is 3.0;

Zi < Z < Z ² where Zi is 0.i5 and Z ² is 0.60; Y

Ai < A < A ² where Ai is 0.i5 and A ² is 3.0;

Preferably

Bi < B < B ² where Bi is 0.9 and B ² is i.5;

Zi < Z < Z ² where Zi is 0.25 and Z ² is 0.50; Y

Ai < A < A ² where Ai is 0.60 and A ² is 2.5.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein the polyethylene, before crosslinking, has a complex viscosity (r|*) at 0.05 rad/sec, which is

X Pas and Xi < X < X ²

where Xi is 7600 and ^X2 is 30000, and

a complex viscosity (r|*) at 300 rad/sec, which is Y Pas, and Yi < Y < Y ² , where Yi is 5 and Y ² complex viscosities (r|*) are determined according to method ISO 672i- i on stabilized polyethylene samples.

Additional embodiments of the polymeric composition are disclosed in which the polyethylene, before crosslinking, has a complex viscosity (r|*) of 0.05 rad/sec, determined according to the ISO 672i-i method on stabilized samples of the polyethylene, which is X Pas, and Xi < X < X ² , where Xi and X ² may each be selected from any of the values given herein for Xi and X ² , respectively.

Even further embodiments of the polymer composition are disclosed in which the polyethylene, before crosslinking, has a complex viscosity (r|*) of 300 rad/sec, determined according to the ISO 672i-i method on stabilized polyethylene samples, which is Y Pas, and Yi < Y < Y ² , where Yi and Y ² can each be selected from any of the values given herein for Yi and Y ² , respectively.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Xi is 76i4.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Xi is 8000.

i0

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein X ¹ is 9000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 10000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 11000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 12000.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein X ¹ is 13000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 14000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 29000.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 28000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 27000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 26000.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein X ² is 25000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 24000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 15000.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 16000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 17000.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 18000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 18100.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein X ¹ is 18200.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 18300.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 18400.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 18500.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 18600.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 18700.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 23500.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 23000.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 22900.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein X ² is 22800.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 22700.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 22600.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ² is 22500.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X2 is 22400.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X2 is 22300.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 10.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 20.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 30.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Y ¹ is 40.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 50.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 60.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 70.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 80.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 90.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 100.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 110.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 120.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 130.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Y ¹ is 140.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 150.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 160.

Still another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 170.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 180.

Still another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 190.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 200.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 210.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Y ¹ is 220.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 230.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 240.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ¹ is 250.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ² is 378.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ² is 375.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ² is 360.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Y ² is 355.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ² is 350.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ² is 345.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ² is 340.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein Y ² is 335.

Another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein Y ² is 330.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein X ¹ is 8000 and X ² is 28000, and wherein Y ¹ is 250 and Y ² is 360.

Yet another embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein X ¹ is 12,000 and X ² is 28,000, and wherein Y ¹ is 250 and Y ² is 330.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein X ¹ is 13,000 and X ² is 27,000, and wherein Y ¹ is 240 and Y ² is 340.

Further disclosed is another embodiment of the polymer composition according to the present invention, as described herein, wherein X ¹ is 13,000 and X ² is 27,000, and wherein Y ¹ is 250 and Y ² is 330.

In further embodiments, the polymer composition may also comprise additional additive(s). Said additional additives comprise:

low molecular weight unsaturated compound(s), for example:

- Crosslinking enhancer(s) mentioned herein, including any specific compound(s), which may contribute to the degree of crosslinking and/or the amount of vinyl groups in the polymer composition.

- One or more scorch retarders (SR) which are defined herein as compounds that reduce scorch formation during extrusion of a polymer composition, at normally used extrusion temperatures, when compared to the same polymer composition extruded without said compound. Burn retardants can also contribute to the total amount of vinyl groups in the polymer composition.

Any contribution of the low molecular weight unsaturated compound(s), for example, the crosslinking enhancer(s) and/or "one or more" burn retardants (SR) to the amount of vinyl groups in the polymer composition is also it is measured according to the method ASTM D6248-98.

The crosslinking enhancer can be a compound containing at least 2 unsaturated groups, such as an aliphatic or aromatic compound, an ester, an ether, an amine or a ketone, containing at least 2 unsaturated groups, such as a cyanurate, an isocyanurate , a phosphate, an ortho-formate, an aliphatic or aromatic ether, or an allyl ester of benzene tricarboxylic acid. Examples of esters, ethers, amines and ketones are compounds selected from the general groups of diacrylates, triacrylates, tetraacrylates, triallylcyanurate, triallylisocyanurate, 3,9-divinyl-2,4,8,10-tetra-oxaspiro[5.5]-undecane (DVS), triallyl trimellitate (TATM) or N,N,N',N',N",N"-hexaallyl-1,3,5-triazine-2,4,6-triamine (HATATA), or any mixture of them. The crosslinking enhancer may be added in an amount of said crosslinking less than 2.0 wt%, eg less than 1.5 wt%, eg less than 1.0 wt%, eg less than 0.75% by weight, for example, less than 0.5% by weight, and the lower limit thereof is, for example, at least 0.05% by weight, for example, at least 0, 1% by weight, based on the weight of the polymer composition.

Burn retardants (SR) can be, for example, unsaturated dimers of alpha-methyl alkenyl aromatic monomers, such as 2,4-di-phenyl-4-methyl-1-pentene, substituted or unsubstituted diphenylethylene, quinone derivatives , hydroquinone derivatives, monofunctional vinyl-containing esters and ethers, monocyclic hydrocarbons having at least two or more double bonds, or mixtures thereof. For example, the scorch retarder can be selected from 2,4-diphenyl-4-methyl-1-pentene, substituted or unsubstituted diphenylethylene, or mixtures thereof.

The amount of scorch retardant may be, for example, equal to or greater than 0.005% by weight, based on the weight of the polymer composition. In addition, the amount of burn retardant may be, for example, equal to or greater than 0.01% by weight, equal to or greater than 0.03% by weight, or equal to or greater than 0.04% by weight, based on the weight of the polymer composition.

Furthermore, the amount of scorch retardant may be, for example, equal to or less than 2.0% by weight, eg, equal to or less than 1.5% by weight, based on the weight of the polymer composition. In addition, the amount of burn retardant can be, for example, equal to or less than 0.8% by weight, equal to or less than 0.75% by weight, equal to or less than 0.70% by weight, or equal to or less at 0.60% by weight, based on the weight of the polymer composition. Likewise, the amount of burn retardant can be, for example, equal to or less than 0.55% by weight, equal to or less than 0.50% by weight, equal to or less than 0.45% by weight or equal to or less at 0.40% by weight, based on the weight of the polymer composition.

Still further, the amount of scorch retardant may be, for example, equal to or less than 0.35 % by weight, eg, equal to or less than 0.30% by weight, based on the weight of the polymer composition. In addition, the amount of burn retardant can be, for example, equal to or less than 0.25% by weight, equal to or less than 0.20% by weight, equal to or less than 0.15% by weight, or equal to or less at 0.10% by weight, based on the weight of the polymer composition. Also, the amount of burn retardant can be, for example, equal to or less than 0.15% by weight, or equal to or less than 0.10% by weight, based on the weight of the polymer composition.

Furthermore, the amount of burn retardant may, for example, be in the range of 0.005 to 2.0% by weight, for example, in the range of 0.005 to 1.5% by weight, based on the weight of the composition. polymeric. Other exemplified ranges are, for example, 0.01 to 0.8 wt%, 0.03 to 0.75 wt%, 0.03 to 0.70 wt% or 0.04 to 0 0.60% by weight, based on the weight of the polymer composition. Furthermore, exemplified ranges are, for example, from 0.01 to 0.60, to 0.55, to 0.50, to 0.45 or, alternatively, to 0.40% by weight, from 0.03 to 0 0.55 or alternatively up to 0.50% by weight, 0.03 to 0.45 or alternatively 0.40% by weight, or 0.04 to 0.45 or alternatively 0.40% by weight, based on the weight of the polymer composition.

Furthermore, scorch retarders (SR) can, for example, be selected from graftable stable organic free radicals, as described in EP1699882, including stable organic free radicals derived from hindered amine, for example: 2-hydroxy derivative, 2,6,6,-tetramethyl piperidinyl oxy (TEMPO), eg 4-hydroxy-TEMPO or bis-TEMPO (eg bis(1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl) sebacate), and, for example, multifunctional molecules having at least two nitroxyl groups derived from oxo-TEMPO, 4-hydroxy-TEMPO, an ester of 4-hydroxy-TEMPO, polymer-bound TEMPO, PROXIL, DOXIL, ditertiary butyl- N-oxyl, dimethyldiphenylpyrrolidin-1-oxyl or 4-phosphonoxy TEMPO.

The graftable stable organic free radicals may be, as described in EP1699882, present in an amount equal to or greater than about 0.005 percent by weight, for example, equal to or greater than about 0.01 percent by weight and equal to or greater than about 0.03 weight percent, based on the weight of the polymer composition.

In addition, stable graftable organic free radicals may be, as described in EP1699882, present in an amount equal to or less than about 20.0 percent by weight, for example, equal to or less than about 10.0 percent by weight. weight percent, eg, equal to or less than about 5.0 weight percent, based on the weight of the polymer composition.

In addition, stable graftable organic free radicals may be, as described in EP1699882, present in an amount between about 0.005 weight percent and about 20.0 weight percent, for example, between 15 and about 0 0.01 weight percent to about 10.0 weight percent, eg, between about 0.03 weight percent and about 5.0 weight percent, based on the weight of the polymer composition.

Furthermore, such additional additive(s) comprise(s) additive(s), such as antioxidants, stabilizers and/or processing aids. As the antioxidant, there may be mentioned sterically hindered or semi-hindered phenol(s), aromatic amine(s), sterically hindered aliphatic amine(s), phosphate(s) organic(s), thio compound(s) and mixtures thereof. As additional additive(s), flame retardant additive(s), water tree retardant additive(s), acid scavenger(s), filler pigment(s) and stabilizer(s) can be mentioned. is) voltage.

Examples of suitable fillers and/or pigments include TiO2, CaCO3, carbon black (eg, conductive carbon black or "UV black", i.e., a carbon black that absorbs ultraviolet radiation), ^huntite , mica, kaolin , aluminum hydroxide (ATH), magnesium dihydroxide (m Dh ) and SiO2.

In yet another embodiment, the polymeric composition according to the present invention further comprises fillers and/or pigments.

Furthermore, said fillers and/or pigments may be comprised in the polymeric composition according to the present invention in amounts of, for example, 0.01 to 5% by weight, for example, 0.01 to 3% by weight or, for example, from 0.01 to 2% by weight.

The polymeric composition may further comprise other polymeric component(s) including unsaturated polymer(s) and/or unsaturated polymer(s), wherein the component(s) additional polymer component(s) are different from said polyethylene.

The polymeric composition can be provided as a powder or granules in any shape and size, including granules. Granules can be produced, for example, after polymerization of said polyethylene, in a well-known manner using conventional pelletizing equipment, such as a pelletizing extruder. The polymeric composition can be provided, for example, in the form of granules.

Furthermore, during the crosslinking of the polymer composition, the decomposition of the crosslinking agent in the polymer composition results in the formation of less than 200 ppm of methane, when measured by the GC analysis method, while, at the same time, maintains a technically desirable level of degree of crosslinking of the polymeric composition, when measured according to the method for determining hot setting. The method for GC analysis and the method for hot-fit determination are described hereinafter in the experimental part under "Determination methods".

An embodiment according to the present invention, a polymer composition, as described herein, is disclosed, wherein decomposition of the crosslinking agent, during crosslinking of the polymer composition, results in the formation of less than 200 ppm methane, when is measured according to the method for GC analysis.

In another embodiment according to the present invention, a polymer composition is disclosed, as described herein, wherein decomposition of the crosslinking agent results in the formation of less than 190 or 180 ppm of methane.

An embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein the decomposition of the crosslinking agent results in the formation of less than 170 or 160 ppm of methane.

A further embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein the decomposition of the crosslinking agent results in the formation of less than 150 ppm of methane.

An embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein the decomposition of the crosslinking agent results in the formation of less than 140, 130, 120, 110 or 100 ppm of methane.

An embodiment of the polymer composition according to the present invention is even disclosed, as described herein, wherein the decomposition of the crosslinking agent results in the formation of less than 115, 110, 105 or 100 ppm of methane.

In addition, the crosslinked polymer composition has a hot-setting elongation, under a load of 20 N/cm2, that is less than 175% at 200°C, when measured on a sample of crosslinked plate according to the method of determination of hot setting. This method is described in more detail herein in the part relating to crosslinking and also in the experimental part under "Determination methods".

An embodiment of the polymeric composition according to the present invention is disclosed, as described herein, wherein the polymeric composition is crosslinked and has a hot-setting elongation, with a load of 20 N/cm2, which is less than 175 %, when measured by the hot-fit determination method.

In another embodiment according to the present invention, the polymeric composition, as described herein, has a hot-setting elongation, with a load of 20 N/cm2, which is less than 170% or, alternatively, less than 160%. .

An embodiment of the polymeric composition according to the present invention is even disclosed, as described herein, wherein said hot-setting elongation, with a load of 20 N/cm2, is less than 150%.

Even a further embodiment of the polymeric composition according to the present invention is disclosed, as described herein, wherein said hot-setting elongation, with a load of 20 N/cm2, is less than 140%.

Even a further embodiment of the polymeric composition according to the present invention is disclosed, as described herein, wherein said hot-setting elongation, with a load of 20 N/cm2, is less than 130%.

Even a further embodiment of the polymeric composition according to the present invention is disclosed, as described herein, wherein said hot-setting elongation, with a load of 20 N/cm2, is less than 120% or, alternatively, is less than 110%.

Another embodiment of the polymeric composition according to the present invention is disclosed, as described herein, wherein the crosslinked polymeric composition has a hot-setting elongation, with a load of 20 N/cm ² , which is less than 100%. .

An embodiment of the polymeric composition according to the present invention is disclosed, as described herein, wherein the crosslinked polymeric composition has a hot-setting elongation, with a load of 20 N/cm ² , which is less than 95%. or, alternatively, it is less than 90%.

An embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein the decomposition of the crosslinking agent results in the formation of less than 150 ppm methane and the crosslinked polymeric composition has a set elongation hot, with a load of 20 N/cm ² , which is less than 100%.

A further embodiment of the polymer composition according to the present invention is disclosed, as described herein, wherein the decomposition of the crosslinking agent results in the formation of less than 150 ppm methane and the crosslinked polymeric composition has an elongation of hot setting, with a load of 20 N/cm ² , which is less than 90%.

Polymer composition polyethylene

In embodiments of the polymer composition, the polyethylene contains said total amount of vinyl groups which is P vinyl groups per 1000 carbon atoms, as described herein. As described herein, P1 < P or P1 < P < P2.

In one embodiment of the polymeric composition, the polyethylene contains said total amount of vinyl groups which is P vinyl groups per 1000 carbon atoms.

In a further embodiment of the polymeric composition, the polyethylene contains the full amount of vinyl groups with P being where P1 is 0.88.

In a particularly preferred embodiment P1 is 0.89 and P2 is 3.0, even more preferably P1 is 0.90 and P2 is 1.5.

In a preferred embodiment, the polymeric composition simultaneously complies with the following:

P1 < P< P2 where P1 is 0.89 and P2 is 3.0;

Z1 < Z < Z2 where Z1 is 0.15 and Z2 is 0.60; Y

A1 < A < A2 where A1 is 0.15 and A2 is 3;

Preferably

P1 < P < P2 where P1 is 0.9 and P2 is 1.5;

Z1 < Z < Z2 where Z1 is 0.25 and Z2 is 0.50; Y

A1 < A < A2 where A1 is 0.60 and A2 is 2.5.

The "amount of vinyl groups" means in this embodiment the "total amount of vinyl groups present in the polyethylene". Herein, polyethylene means both a homopolymer, to which unsaturation has been provided by a chain transfer agent, and a copolymer, wherein the unsaturation is provided by polymerization of a monomer together with at least one polyunsaturated comonomer, optionally in the presence of a chain transfer agent and also optionally in combination with other comonomers.

In one embodiment, the polyethylene is an unsaturated copolymer which, as already mentioned herein, comprises one or more polyunsaturated comonomers. Furthermore, said vinyl groups (P) present in the unsaturated copolymer may originate from said polyunsaturated comonomer, a polyethylene production process and, optionally, from any chain transfer agent used.

When the polyethylene of the polymeric composition is an unsaturated copolymer comprising at least one polyunsaturated comonomer, then the polyunsaturated comonomer is a linear carbon chain with at least 8 carbon atoms and at least 4 carbon atoms between the non-conjugated double bonds, of which at least one is terminal.

As for suitable polymeric materials for the polymeric composition, said polyethylene can be any polymer having relevant characteristics, as defined herein, for the polyethylene of the exemplified polymeric composition. The polyethylene can be selected from homopolymers of polyethylene as well as copolymers of polyethylene with one or more comonomers. Polyethylene can be unimodal or multimodal with with respect to molecular weight distribution and/or comonomer distribution, which expressions have a well-known meaning.

In one embodiment, the polyethylene is a homopolymer of ethylene.

In one embodiment of the polymer composition, the polymer composition is made by a process comprising the homopolymerization of ethylene.

In an exemplified embodiment of the polymer composition, the polyethylene is an unsaturated copolymer of polyethylene with at least one polyunsaturated comonomer and optionally with one or more comonomer(s).

Said polyethylene unsaturated copolymer is an ethylene unsaturated copolymer.

In one embodiment of the present invention, a polymer composition is disclosed, as described herein, wherein the polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer and with zero, one or more, eg, zero, one, two or three other comonomer(s), and wherein said total amount of vinyl groups (B) present in the polymeric composition includes vinyl groups originating from at least said polyunsaturated comonomer, for example, diene.

In an exemplified embodiment of the polymer composition, the polymer composition is made by a process comprising blending an ethylene unsaturated copolymer with the crosslinking agent.

Said ethylene copolymer may be an LDPE copolymer produced in a continuous high pressure polymerization process, wherein ethylene is copolymerized with at least one polyunsaturated comonomer and optionally with one or more comonomer(s), optionally in the presence of an agent. chain transfer.

The optional additional comonomer(s) present in the polyethylene, e.g., ethylene copolymer, is different from the "backbone" monomer and may be selected from an ethylene and an alpha-olefin(s). higher, for example, C3-C20 alpha-olefin(s), for example, a cyclic alpha-olefin of 5 to 12 carbon atoms or a straight or branched chain alpha-olefin of 3 to 12 carbon atoms, such as propylene, 1- butene, 1-hexene, 1-nonene or 1-octene, as well as polar comonomer(s).

In one embodiment, the straight or branched chain alpha-olefin is a straight or branched chain alpha-olefin of 3 to 6 carbon atoms.

In another embodiment, the straight chain alpha-olefin is propylene.

It is known that, for example, propylene can be used as a comonomer or as a chain transfer agent (CTA), or both, so it can contribute to the total amount of vinyl groups in polyethylene, P. Herein, when using copolymerizable CTA, such as propylene, the copolymerized CTA is not calculated for comonomer content.

In an exemplary embodiment of the polymer composition, the polyethylene is an unsaturated LDPE polymer, eg, an unsaturated LDPE copolymer comprising at least one comonomer that is a polyunsaturated comonomer (referred to herein as LDPE copolymer).

Furthermore, said polyunsaturated comonomer may be a diene, for example, (1) a diene comprising at least 8 carbon atoms, the first carbon-carbon double bond is terminal and the second carbon-carbon double bond is non-conjugated with the first (dienes from group 1). Exemplified dienes (1) may be selected from non-conjugated Cs to C14 dienes or mixtures thereof, for example, selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene, 7-methyl-1,6-octadiene, 9-methyl-1,8-decadiene or mixtures thereof. In another embodiment, diene (1) is selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene, or any mixture thereof.

Another embodiment according to the present invention of the polymeric composition, as described herein, is disclosed, wherein the polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer, wherein the polyunsaturated comonomer is a linear carbon chain with at least one polyunsaturated comonomer. least 8 carbon atoms and at least 4 carbon atoms between non-conjugated double bonds, at least one of which is terminal, eg Cs to C14 non-conjugated diene, eg selected from 1,7-octadiene, 1 ,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene or mixtures thereof.

In a preferred embodiment, the polyethylene is a copolymer of ethylene and 1,7-octadiene.

Furthermore, a further embodiment of the polymeric composition according to the present invention is described, as described herein, wherein the polyethylene is an unsaturated LDPE homopolymer or copolymer produced in a continuous high pressure polymerization process, for example, an LDPE copolymer of ethylene with one or more polyunsaturated comonomer(s) and with zero, one or more comonomer(s).

In addition to or as an alternative to the dienes (1) listed herein, the diene can also be selected from other types of polyunsaturated dienes (2), such as one or more siloxane compounds having the following formula (dienes from the group (2 )):

CH ² =CH-[SiR-iR ² -O]n-SiRiR ² -CH=CH ² ,

where n = 1 to 200, and R1 and R2, which may be the same or different, are selected from C1 to C4 alkyl groups and/or C1 to C4 alkoxy groups.

Furthermore, R1 and/or R2 can be, for example, methyl, methoxy or ethoxy. Furthermore, n may, for example, be from 1 to 100, for example from 1 to 50. As an example, divinylsiloxanes, for example a,u>-divinylsiloxane, may be mentioned. Exemplified polyunsaturated comonomers for polyethylene are the group (1) dienes as defined herein. The polyethylene can, for example, be a copolymer of ethylene with at least one diene selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene or any mixture thereof, and optionally with one or more other comonomers. It is also exemplified that said polyethylene is the unsaturated LDPE copolymer mentioned herein. It may comprise other comonomers, for example. polar comonomer(s), alpha-olefin comonomer(s), non-polar comonomer(s), or any mixture thereof.

As the polar comonomer, compound(s) containing hydroxyl group(s), alkoxy group(s), carbonyl group(s), carboxyl group(s), ether group(s) or ester group(s) can be used. , or a mixture thereof.

Furthermore, a nonpolar comonomer is a compound that does not contain hydroxyl group(s), alkoxy group(s), carbonyl group(s), carboxyl group(s), ether group(s), and ester group(s). .

In a further embodiment, compounds containing carboxyl and/or ester group(s) are used and, for example, the compound is selected from the groups of acrylate(s), methacrylate(s) or acetate(s), or any mixture thereof. If present in said unsaturated LDPE copolymer, the polar comonomer may be selected, for example, from the group of alkyl acrylates, alkyl methacrylates, or vinyl acetate, or a mixture thereof. Furthermore, said polar comonomers may be selected from, for example, C1 to C6 alkyl acrylates, C1 to C6 ^{alkyl methacrylates} , or vinyl acetate. Even said polar copolymer comprises a copolymer of ethylene with C1 to C4 alkyl acrylate, such as methyl, ethyl, propyl or butyl acrylate, or vinyl acetate, or any mixture thereof.

The polyethylene of the polymer composition described herein can be prepared using, among others, any conventional polymerization process and equipment, the conventional means described herein for providing unsaturation, and any conventional means for adjusting the MFR2 to control and adjusting the process conditions to achieve the desired balance between MFR2 and the amount of vinyl groups in the polymerized polymer. Unsaturated LDPE polymer, as defined herein, eg unsaturated LDPE copolymer of the polymer composition is produced in a continuous high pressure reactor by free radical initiated polymerization (referred to as high pressure radical polymerization). Usable high pressure (HP) polymerization and adjustment of process conditions are well known and described in the literature, and can be readily used by one skilled in the art to provide the inventive balance described herein. Continuous high pressure polymerization can be carried out in a tubular reactor or in an autoclave reactor, for example, in a tubular reactor. Described herein is an embodiment of the HP continuous process for polymerizing ethylene optionally together with one or more comonomers, eg, with at least one or more polyunsaturated comonomers, in a tubular reactor to obtain an LDPE homopolymer or copolymer as defined at the moment. The process can also be adapted to other polymers.

Furthermore, the polyethylene of the polymer composition described herein can be produced in a high pressure reactor by free radical polymerization (so-called high pressure radical polymerization). Free radical initiated polymerization is very fast and therefore well suited for a continuous process where careful control of process parameters can be obtained by continuous checks and adjustments. In the high pressure radical polymerization process there is a continuous feed of ethylene and initiator. The high pressure radical polymerization process is preferably an autoclave or a tubular process, more preferably a tubular reactor. A high-pressure tubular process typically produces a polyethylene with a narrower molecular weight distribution and a lower degree of long-chain branching and other branching structure compared to a polyethylene produced in an autoclave process if high-pressure conditions are used. similar process, such as similar temperature profile, similar pressure, and initiator feed Similary. Typically, a tubular reactor also has more favorable production economics because it has higher ethylene conversion rates.

In another embodiment, the polyethylene of the polymer composition of the present invention is produced in a high pressure continuous tubular reactor.

Compression: Ethylene is fed to a compressor primarily to allow handling of large quantities of ethylene at controlled pressure and temperature. Compressors are usually piston compressors or diaphragm compressors. The compressor is usually a series of compressors that can work in series or in parallel. The most common is 2-5 compression steps. Recycled ethylene and comonomers can be added at feasible points depending on pressure. The temperature is usually low, usually in the range of less than 200 °C or less than 100 °C. Said temperature may, for example, be less than 200 °C.

Tubular reactor: The mixture is fed to the tubular reactor. The first part of the tube is for adjusting the temperature of the ethylene feed; the usual temperature is 150-170 °C. The radical initiator is then added. As the radical initiator, any compound or a mixture thereof which decomposes into radicals at an elevated temperature can be used. Usable radical initiators are commercially available. The polymerization reaction is exothermic. There may be several radical initiator injection points, eg 1-5 points, usually provided with separate injection pumps. Ethylene and optional comonomer(s) may also be added at any time during the process, at any zone of the tubular reactor and/or from one or more injection points, as is well known. The reactor is continuously cooled, for example by water or steam. The higher temperature is called the maximum temperature and the lower temperature is called the radical initiator temperature. The "lowest temperature" means herein the reaction start temperature, which is called the initiation temperature, which is "lowest" as is apparent to a person skilled in the art.

Suitable temperatures range from 80 to 350 °C and pressure from 100 to 400 MPa. The pressure can be measured at least at the compression stage and after the tube. Temperature can be measured at various points during all steps. High temperature and high pressure generally increase production. The use of various temperature profiles selected by one skilled in the art will allow control of the polymer chain structure, i.e. long chain branching and/or short chain branching, density, MFR, viscosity, molecular weight distribution. , etc.

The reactor is conventionally terminated with a valve. The valve regulates the reactor pressure and depressurizes the reaction mixture from reaction pressure to separation pressure.

Separation: The pressure is normally reduced to about 10 to 45 MPa, for example to about 30 to 45 MPa. The polymer is separated from unreacted products, eg, gaseous products, such as optional monomer or comonomers, and most of the unreacted products are recovered. Low molecular weight compounds, i.e. wax, are generally removed from the gas. The pressure can be further reduced to recover and recycle unused gaseous products such as ethylene. The gas is usually cooled and cleaned before being recycled.

Then, the molten polymer obtained is usually mixed and granulated. Optionally, or in some embodiments, additives may be added at the mixer. More details on the production of ethylene (co)polymers by high pressure radical polymerization can be found in the Encyclopedia of Polymer Science and Engineering, Vol. 6 (1986), pp. 383-410.

The MFR ² of the polyethylene, eg, LDPE copolymer, can be adjusted by using, eg, chain transfer agent during polymerization, and/or by adjusting the reaction temperature or pressure.

When preparing the LDPE copolymer of the invention, then, as is known, the amount of vinyl groups can be adjusted by polymerizing ethylene, for example, in the presence of one or more polyunsaturated comonomer(s), agent(s). ) chain transfer, or both, using the desired feed ratio of C ² to polyunsaturated comonomer and/or chain transfer agent, depending on the nature and number of carbon-carbon double bonds desired for the LDPE copolymer. Ia WO 9308222 describes a high pressure radical polymerization of ethylene with polyunsaturated monomers, such as a,w-alkadienes, to increase the unsaturation of an ethylene copolymer. The unreacted double bonds provide pendant vinyl groups to the polymer chain formed at the site, where the polyunsaturated comonomer was incorporated by polymerization. As a result, the unsaturation can be evenly distributed throughout the polymer chain in the form of random copolymerization. Also, for example, WO 9635732 describes the high pressure radical polymerization of ethylene and a certain type of polyunsaturated a,u>-divinylsiloxanes. Furthermore, as is known, eg propylene can be used as a chain transfer agent to provide double bonds, thus it can also be partially copolymerized with ethylene.

The alternative unsaturated LDPE homopolymer can be produced analogously to the process conditions described herein as the unsaturated LDPE copolymer, except that ethylene is polymerized only in the presence of a chain transfer agent.

An example of the polyethylene, for example the LDPE copolymer, of the present invention may have a density, when measured on the polyethylene according to method A:2012 of ISO 1183-1, for example greater than 0.860 g/cm3, greater than 0.870, greater than 0.880, greater than 0.885, greater than 0.890, greater than 0.895, greater than 0.900, greater than 0.905, greater than 0.910 or greater than 0.915 g/cm3.

Another example of polyethylene, for example the LDPE copolymer, of the present invention may have a density, when measured on polyethylene according to method A:2012 of ISO 1183-1, of up to 0.960 g/cm3, less than 0.955, less than 0.950, less than 0.945, less than 0.940, less than 0.935 or less than 0.930 g/cm3.

In another embodiment, the density range, when measured on polyethylene according to method A:2012 of ISO 1183-1, is 0.915 to 0.930 g/cm3.

Furthermore, said unsaturated copolymer, for example the LDPE copolymer of the polymeric composition comprises comonomer(s) in a total amount of up to 45% by weight, for example from 0.05 to 25% by weight, or for example from 0.05 to 25% by weight. 0.1 to 15% by weight, based on the amount of polyethylene.

An exemplified polyethylene of the polymer composition is crosslinkable.

In an exemplified embodiment, the polymeric composition consists of at least one polyethylene. The polymer composition may comprise additional components such as additives described herein which may be added in admixture with a carrier polymer, ie in a so-called master batch.

In a further embodiment, the polymeric composition may comprise polyethylene, as described herein, together with the crosslinking agent and together with 0, 1, 2, 3, 4, 5, 6 or more additives, and wherein the polymeric composition is in the form of granules.

Another embodiment of the present invention discloses a process for producing a polymeric composition as described herein, the process comprising mixing the polyethylene with the crosslinking agent.

end applications

An embodiment of the present invention provides an article obtained from a process comprising the use of a polymeric composition as described herein, wherein the article is, for example, a cable, for example a power cable

A further embodiment of the present invention provides an article that is made from a process comprising the use of the polymer composition as described herein.

Yet another embodiment of the present invention provides an article comprising layer(s), for example insulating layer(s), which is/are made from a polymeric composition as described herein, wherein the item is, for example, a cable, for example a power cable

In one embodiment of the present invention, an article, eg a cable, is provided, wherein the cable, eg power cable, comprises a layer which is made from said polymeric composition. In another embodiment of the present invention, an article is provided, wherein said article is crosslinkable and is obtained from a process comprising the use of the polymeric composition as described herein. In yet another embodiment of the present invention, an article is provided, wherein said article comprises the polymeric composition as described herein.

In another embodiment of the present invention, an article is provided, wherein said article is crosslinked and is obtained from a process comprising the use of the polymeric composition as described herein. Another embodiment of the present invention provides an article, which is a cable, for example a power cable

Furthermore, the invention is well suited for W&C applications, where an article, for example a cable, is crosslinkable and comprises one or more layers, where at least one layer is made from the polymer composition as described in the present.

Furthermore, yet another embodiment of the present invention is provided, wherein said at least one layer comprises the polymeric composition as described herein.

Another embodiment of the present invention provides a power cable comprising layer(s), eg insulating layer(s), which is/are made from the polymeric composition as described herein.

Yet another embodiment of the present invention is provided, wherein said item is an AC power cord.

Another embodiment of the present invention is provided wherein said article is a DC power cable. Furthermore, at least the layer of the cable obtained from the polymeric composition can be, for example, an insulating layer.

Furthermore, at least the layer of the cable comprising the polymeric composition can be, for example, an insulating layer.

Furthermore, the cable of the present invention can be, for example, a power cable comprising at least one inner semiconductive layer, an insulating layer and an outer semiconductive layer in a certain order, where at least the insulating layer is obtained by from the polymer composition as described herein.

In addition, yet another embodiment of the present invention is provided, wherein the term "is derived from the polymer composition" also encompasses the feature "comprises the polymer composition". Power cord herein means a cord that transfers power by operating at any voltage. The voltage applied to the power cable can be AC, DC, or transient (impulse). In one embodiment, the multilayer article is a power cable operating at voltages greater than 6 kV.

A further embodiment of the present invention discloses a process for the production of an article, as described herein, which process comprises the use of a polymeric composition, as described herein.

Furthermore, the invention provides a process for the production of the article described herein, comprising the following steps: a) forming an article, wherein the process comprises the polymer composition as described herein. Said process may, for example, comprise at least the following steps:

a ⁰ ) melt blending a polymeric composition as described herein optionally together with other components, and

a) forming a cable obtained from the polymeric composition as described herein.

A further embodiment discloses the formation of a cable comprising the polymer composition as described herein.

"Melt blending" is a well-known blending method, where the polymeric components are blended at an elevated temperature, which is typically higher, e.g. at least 20-25°C above the melting or softening point of the polymer components.

In one embodiment, a cable is produced comprising a conductor surrounded by one or more layers, wherein the process comprises the step of a) applying the polymeric composition, as described herein, to a conductor to form at least one of said layers surrounding the conductor.

Therefore, in step (a) at least one layer of said one or more layers is applied and obtained by using the polymer composition as described herein.

Furthermore, the cable production process exemplified herein may, for example, comprise at least two of the following steps:

a ⁰ ) melt mixing said polymeric composition as described herein, optionally together with other components, and then

a) apply the mixture by fusion obtained in step a ⁰ ) on a conductor to form at least one layer.

The polymeric composition, as described herein, can be introduced in step a ⁰ ) of the process, for example, in the form of granules and the mixing, that is, the melt mixing, is carried out at an elevated temperature that melts (or softens) the polymeric material to allow it to be processed.

Furthermore, the layers can, for example, be a) applied by (co)extrusion. The term "(co)extmsion" means herein that in the case of two or more layers, said layers may be extruded in separate steps, or at least two or all of said layers may be coextruded in a single extrusion step, such as is known in the art.

In an exemplified embodiment, the crosslinkable polymeric composition may comprise a crosslinking agent before the polymeric composition is used for cable production, whereby the polyethylene and crosslinking agent may be mixed by any conventional mixing process, e.g. , by adding the crosslinking agent to a melt of a polymer composition, for example, in an extruder, as well as by adsorption of liquid peroxide, peroxide in liquid form, or peroxide dissolved in a solvent on a solid polymer composition, for example , granules thereof. Alternatively, in this embodiment, the polyethylene and crosslinking agent may be mixed by any conventional mixing process. Exemplary blending methods include melt blending, eg, in an extruder, as well as adsorption of liquid peroxide, peroxide in liquid form, or a peroxide dissolved in a solvent from a polymer composition or granules thereof. The obtained polymeric composition of components, for example, but not limited to, the polyethylene and the crosslinking agent, is then used for a process of preparing an article, for example, a cable.

In another embodiment, the crosslinking agent may be added, for example, in step ao) during the preparation of the crosslinkable article, and also forms the polymer composition of the present invention. When the crosslinking agent is added during the article preparation process, then, for example, the crosslinking agent, as described herein, is added in liquid form at room temperature, or is preheated above the melting point thereof or dissolved in a carrier medium, as is known in the art.

The polymer composition of the present invention may also comprise additional additive(s), or additional additives may be mixed into the polymer composition during a process of preparing an article comprising the polymer composition.

Therefore, the process of the invention may, for example, comprise the following steps:

- aoo) providing said step ao) with said polymeric composition as described herein, comprising at least one polyethylene, and

a crosslinking agent,

- ao) melt-mixing the polymeric composition optionally together with other components, and

a) applying the mixture by melting obtained from step ao) on a conductor to form at least one of said one or more layers of cable.

Alternatively, the process of the invention comprises the following steps:

- aoo) providing said step ao) with said polymeric composition as described herein, comprising at least one polyethylene,

- aoo') add to said polymeric composition at least one crosslinking agent,

- ao) mixing by melting the polymeric composition and the crosslinking agent, optionally together with other components, and

- a) applying the mixture by melting obtained from step ao) on a conductor to form at least one of said one or more layers of cable.

In the exemplified process, melt blending ao) of the polymer composition alone is performed in a mixer or an extruder, or any combination thereof, at elevated temperature and, if the crosslinking agent is present, also below the crosslinking temperature used subsequently. After melt-blending ao), eg in said extruder, the resulting melt-blended layer material is then eg a) (co-)extruded onto a conductor in a manner well known in the art. Mixers and extruders, such as single or twin screw extruders, which are conventionally used for the preparation of cables, are suitable for the process of the invention.

The exemplified embodiment of the process provides the preparation of a crosslinkable cable, for example a crosslinkable power cable, wherein the process comprises an additional step of b) crosslinking at least one layer of cable obtained in step a) comprising a polyethylene crosslinkable of the polymeric composition, wherein the crosslinking is carried out in the presence of a crosslinking agent, for example, a peroxide.

It is understood and known that also the other cable layers and the materials thereof, if present, can be crosslinked at the same time, if desired.

Crosslinking can be carried out under crosslinking conditions, typically by high temperature treatment, for example, at a temperature above 14°C, for example, above 15°C, such as within the range of 16° to 35°C. , depending on the crosslinking agent used, as is well known in the art. Typically, the crosslinking temperature is at least 2°C higher than the temperature used in melt blending step ao) and can be estimated by a person skilled in the art.

As a result, a crosslinked cable is obtained that comprises at least one crosslinked layer of the polymeric composition of the invention.

In another embodiment according to the present invention, a polymeric composition is disclosed, wherein said total amount of vinyl groups, B, originates from (in addition to vinyl groups originating from free radical initiated polymerization):

i) polyunsaturated comonomer(s),

ii) chain transfer agent(s),

iii) low molecular weight unsaturated compound(s), e.g. crosslinking enhancer(s) and/or burn retardant(s), or

iv) any mixture of (i) to (iii).

In general, "vinyl group" means herein CH ² =CH- moieties which may be present in any of i) to iv).

The i) polyunsaturated comonomers and ii) the chain transfer agents are described herein in relation to the polyethylene of the polymeric composition according to the present invention.

The low molecular weight compound(s) iii), if present, may be added to the polymer composition.

Furthermore, the low molecular weight compound(s) iii) may, for example, be crosslinking enhancer(s) which may also contribute to said total amount of vinyl groups, B, of the polymer composition . The crosslinking enhancer(s) may be, for example, a compound containing at least 2 unsaturated groups, such as an aliphatic or aromatic compound, an ester, an ether or a ketone, containing at least 2 unsaturated groups , such as a cyanurate, an isocyanurate, a phosphate, an ortho-formate, an aliphatic or aromatic ether, or an allyl ester of benzene tricarboxylic acid. Examples of esters, ethers, amines and ketones are compounds selected from the general groups of diacrylates, triacrylates, tetraacrylates, triallylcyanurate, triallylisocyanurate, 3,9-divinyl-2,4,8,10-tetra-oxaspiro[5.5]-undecane (DVS), triallyl trimellitate (TATM) or N,N,N',N',N",N"-hexaaliM,3,5-triazine-2,4,6-triamine (HATATA), or any mixture of the same. The crosslinking enhancer may be added in an amount of said crosslinking less than 2.0 wt%, eg less than 1.5 wt%, eg less than 1.0 wt%, eg less than 0.75% by weight, for example, less than 0.5% by weight, and the lower limit thereof is, for example, at least 0.05% by weight, for example, at least 0, 1% by weight, based on the weight of the polymer composition.

Furthermore, the low molecular weight compound(s) iii) may be, for example, scorch retarder(s) (SR) which may also contribute to said total amount of vinyl groups, B, of the polymer composition.

The scorch retarders (SR) can be, for example, as already described herein, unsaturated dimers of alphamethylalkenyl aromatic monomers, such as 2,4-di-phenyl-4-methyl-1-pentene, substituted diphenylethylene or unsubstituted, quinone derivatives, hydroquinone derivatives, vinyl-containing monofunctional esters and ethers, monocyclic hydrocarbons having at least two or more double bonds, or mixtures thereof. For example, the scorch retarder can be selected from 2,4-diphenyl-4-methyl-1-pentene, substituted or unsubstituted diphenylethylene, or mixtures thereof.

The amount of scorch retardant may be, for example, equal to or greater than 0.005% by weight, based on the weight of the polymer composition. In addition, the amount of burn retardant may be, for example, equal to or greater than 0.01% by weight, equal to or greater than 0.03% by weight, or equal to or greater than 0.04% by weight, based on the weight of the polymer composition.

Furthermore, the amount of scorch retardant may be, for example, equal to or less than 2.0% by weight, eg, equal to or less than 1.5% by weight, based on the weight of the polymer composition. In addition, the amount of burn retardant can be, for example, equal to or less than 0.8% by weight, equal to or less than 0.75% by weight, equal to or less than 0.70% by weight, or equal to or less at 0.60% by weight, based on the weight of the polymer composition. Likewise, the amount of burn retardant can be, for example, equal to or less than 0.55% by weight, equal to or less than 0.50% by weight, equal to or less than 0.45% by weight or equal to or less at 0.40% by weight, based on the weight of the polymer composition.

Still further, the amount of scorch retardant may be, for example, equal to or less than 0.35% by weight, eg, equal to or less than 0.30% by weight, based on the weight of the polymer composition. In addition, the amount of burn retardant can be, for example, equal to or less than 0.25% by weight, equal to or less than 0.20% by weight, equal to or less than 0.15% by weight, or equal to or less at 0.10% by weight, based on the weight of the composition polymeric. Also, the amount of burn retardant can be, for example, equal to or less than 0.15 % by weight, or equal to or less than 0.10% by weight, based on the weight of the polymer composition.

Furthermore, the amount of burn retardant may, for example, be in the range of 0.005 to 2.0% by weight, for example, in the range of 0.005 to 1.5% by weight, based on the weight of the composition. polymeric. Other exemplified ranges are, for example, 0.01 to 0.8 wt%, 0.03 to 0.75 wt%, 0.03 to 0.70 wt% or 0.04 to 0 0.60% by weight, based on the weight of the polymer composition. Furthermore, exemplified ranges are, for example, from 0.01 to 0.60, to 0.55, to 0.50, to 0.45 or, alternatively, to 0.40% by weight, from 0.03 to 0 0.55 or alternatively up to 0.50% by weight, 0.03 to 0.45 or alternatively 0.40% by weight, or 0.04 to 0.45 or alternatively 0.40% by weight, based on the weight of the polymer composition.

Furthermore, the scorch retarders (SR) can also, for example, be selected from graftable stable organic free radicals, as described in EP1699882 and as already described herein.

The polyethylene of the polymeric composition can be, for example, a copolymer of monomer units with units of at least one unsaturated comonomer and zero, one, two or three different comonomer(s), and comprises at least vinyl groups originating from the comonomer polyunsaturated.

In addition, the polyethylene of the polymer composition may comprise from about 0.05 to about 0.10 vinyl groups per 1000 carbon atoms (C atoms) originating from free radical initiated polymerization.

According to the present invention, each feature of any of the embodiments disclosed herein, in any category of the present invention, may be freely combined with any feature of any of the other embodiments disclosed herein.

Determination methods

Unless otherwise indicated in the description or experimental part, the following methods were used for property determinations.

Melt Flow Index

The melt flow rate (MFR) is determined according to the method ISO 1133-1:2011 and is indicated in g/10 min. The MFR is an indication of the fluidity and thus the processability of the polymer, here polyethylene, or the polymer composition. The higher the melt flow index, the lower the viscosity of the polymer or polymer composition. The MFR is determined at 190 °C for polyethylenes and can be determined at different loadings, such as 2.16 kg (MFR2) or 21.6 kg (MFR21).

Density

The density is measured on the polymer, i.e. on the polyethylene, according to method A:2012 of ISO 1183-1. Sample preparation is performed by compression molding according to ISO 17855-2:2016.

ASTM D3124-98 and ASTM D6248-98 methods, to determine the number of double bonds in the polymer composition or in the polymer, i.e. polyethylene

The ASTM D6248-98 method is applied for the determination of double bonds, both in the polymeric composition and in polyethylene. The determination of the double bonds of the polymeric composition is carried out on the polyethylene (to determine the parameter P) or, alternatively, on the polymeric composition (to determine the parameter B). The polymeric composition and the polyethylene will be referred to hereinafter in this description of the method as "the composition" and "the polymer", respectively.

The ASTM D3124-98 and ASTM D6248-98 methods include, on the one hand, a procedure for determining the number of double bonds/1000 C atoms that is based on the ASTM D3124-98 method. A detailed description for the determination of vinylidene groups/1000 C atoms based on 2,3-dimethyl-1,3-butadiene is given in ASTM method D3124-98. Detailed descriptions for the determination of vinyl and trans-vinylene groups/1000 C atoms based on 1-octene and trans-3-hexene, respectively, are provided in ASTM method D6248-98. The sample preparation procedure described therein has been applied here for the determination of vinyl groups/1000 C atoms and trans-vinylene groups/1000 C atoms in the present invention. ASTM D6248-98 suggests possible inclusion of the ASTM D3124-98 bromination procedure, but the samples with respect to the present invention were not brominated. We have shown that the determination of vinyl groups/1000 C atoms and trans-vinylene groups/1000 C atoms can be performed without significant interference, even without subtracting the spectra of the brominated samples. In order to determine the extinction coefficient of these two types of double bonds, the following two compounds have been used: 1-decene for vinyl and trans-4-decene for trans-vinylene, and the procedure described in ASTM-D6248-98 was followed with the exception mentioned previously.

The total amount of vinyl bonds, vinylidene bonds, and trans-vinylene double bonds in the "polymer" was analyzed by IR spectrometry and reported as the amount of vinyl bonds, vinylidene bonds, and trans-vinylene bonds per 1000 carbon atoms.

In addition, the total amount of vinyl and trans-vinylene double bonds of "the composition", with a possible contribution of double bonds from any low molecular weight unsaturated compound (iii) used, can also be analyzed by IR spectrometry and given as the number of vinyl bonds, vinylidene bonds, and trans-vinylene bonds per 1000 carbon atoms.

The composition or polymer to be analyzed was compressed into thin films with a thickness of 0.5-1.0 mm. The actual thickness was measured. FT-IR analysis was performed on a Perkin Elmer Spectrum One. Two scans were recorded with a resolution of 4 cm ^-1

A baseline was drawn from 980 cm ^-1 to about 840 cm ^-1 . Peak heights were determined to be about 910 cm ^-1 for vinyl and about 965 cm ^-1 for trans-vinylene. The number of double bonds/1000 carbon atoms was calculated using the following formulas:

frans-viniene/IOOG C atoms =(14 x Absy[15.14 x L x D}

where

Abs: absorbance (peak height)

L: film thickness in mm

D: material density (g/cm3)

The molar absorbent power ,£ , that is, 13.13 and 15.14, respectively, in the previous calculations was determined as l•mol-1•mm■1 through:

where Abs is the maximum absorbance defined as the height of the peak, C the concentration (moH-1) and L the thickness of the cell (mm).

The methods ASTM D3124-98 and ASTM D6248-98, on the other hand, also include a procedure to determine the molar extinction coefficient. At least three 0.18 moM-1 solutions in carbon disulfide (CS ² ) were used and the mean value of the molar extinction coefficient was used.

The amount of vinyl groups originating from the polyunsaturated comonomer per 1000 carbon atoms was determined and calculated as follows:

The polymer to be analyzed and a reference polymer have been produced in the same reactor, basically using the same conditions, that is, similar maximum temperatures, pressure and production rate, but with the only difference that the polyunsaturated comonomer is added to the polymer. to be analyzed and is not added to the reference polymer. The total amount of vinyl groups in each polymer was determined by FT-Ir measurements, as described herein. Then, the base level of vinyl groups, i.e. those formed by the process and chain transfer agents that result in vinyl groups (if present), is assumed to be the same for the reference polymer and the polymer. to be tested, with the sole exception that a polyunsaturated comonomer is also added to the reactor in the polymer to be tested. This base level is then subtracted from the measured number of vinyl groups in the polymer to be tested, resulting in the number of vinyl groups/1000 C atoms, resulting from the polyunsaturated comonomer.

Methods ASTM D3124-98 and ASTM D6248-98 include a calibration procedure for measuring the double bond content of a low molecular weight unsaturated compound (iii), if present (referred to below as compound)

The molar absorbent power of the compound (for example, a crosslinking enhancer or a burn retardant compound as exemplified in the description) can be determined with said methods according to ASTM D624898. At least three solutions of the compound in CS ² (carbon disulfide) are prepared. The concentrations of the solutions used are close to 0.18 mol/l. Solutions are analyzed with FTIR and scanned at a resolution of 4 cm-1 in a liquid cell with a path length of 0.1 mm. The maximum intensity of the absorbance peak that relates to the unsaturated moiety of the compound(s) (each type of carbon-carbon double bond present) is measured.

The molar absorbent power, £, in l^mol-1^ mm-1 for each solution and type of double bond is calculated using the following equation:

C = concentration of each type of carbon-carbon double bond to be measured, mol/l

L = cell thickness, mm

Abs = maximum absorbance (peak height) of the peak of each type of carbon-carbon double bond to be measured, mol/l.

The average molar absorbing power, £, is calculated for each type of double bond. In addition, the average molar absorbent power, £, of each type of carbon-carbon double bond can be used to calculate the concentration of double bonds in the reference polymer and the polymer samples to be tested.

Rheology, dynamic method (viscosity) ISO 6721-1:

The dynamic rheological properties of the polymer, herein polyethylene, or the polymer composition (also measured on polyethylene) can be determined using a controlled stress rheometer, using a parallel plate geometry (25 mm diameter) and a space of 1.8mm between top and bottom plate. Prior to testing, samples should be stabilized by dry blending granules together with 0.25-0.3% Irganox B225. Irganox B 225 is a 50% blend of Irganox 1010, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), CAS no. 6683-19-8 and 50% Irgafos 168, tris(2,4-ditert-butylphenyl)phosphite, CAS no. 31570 04-4. Note that adding an antioxidant, here Irganox B225, is not normally the standard procedure of ISO method 6721-1.

The frequency sweep test, ie the "rheology method, dynamic (viscosity)", was performed according to the ISO standard method, ISO 6721-1 with an angular frequency range of 500 to 0.02 rad/s. All experiments were carried out in a nitrogen atmosphere at a constant temperature of 190 °C and stress within the linear viscoelastic region. During analysis, storage modulus (G'), loss modulus (G"), complex modulus (G*), and complex viscosity (r|*) were recorded and plotted against frequency (M). The measured values of complex viscosity (r|*) at an angular frequency of 0.05, 100 and 300 rad/s are taken from the test The abbreviations of these parameters are V0.05, V100 ^and V300 respectively.

The zero viscosity value n* ⁰ is calculated using the Carreau-Yasuda model. For cases where the use of this model for zero shear viscosity estimation is not recommended, a low shear rate rotational shear test is performed. This test is limited to a shear rate range of 0.001 to 1 s_1 and a temperature of 190 °C.

Preparation of crosslinked plate, that is, the method for crosslinking plate:

Preparation of crosslinked plate when dicumyl peroxide (DCP) or tert-butylcumyl peroxide (TBCP) is used as peroxide, i.e. the method for crosslinking plate

The crosslinked plate is prepared from pellets of the test polymer composition, that is, the polymer composition according to the present invention and the comparative polymer composition, which were compression molded using the following conditions: First, the pellets are melted at 120 °C for 1 minute at a pressure of 61 N/cm2. Then the temperature is increased to 180 °C at a rate of 18 K/min and at the same time the pressure is increased to 614 N/cm2. The temperature is maintained at 180°C for 10 minutes. the plates are then crosslinked by means of the peroxide present in the polymeric composition. The total crosslinking time is 14 minutes, which includes the time to increase the temperature from 120 to 180°C. After the crosslinking of the crosslinked plates, that is, the crosslinked polymer composition according to the present invention and the comparative crosslinked polymer composition, is completed, it is cooled to room temperature with a cooling rate of 15 K/min still under pressure. The final thickness of the plates is 1.5 mm.

Preparation of crosslinked plate when using 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, i.e. Trigonox® 145-E85, (T145E85) as peroxide, i.e. the method for crosslinking plate

The crosslinked plate is prepared from pellets of the test polymer composition, that is, the polymer composition according to the present invention and the comparative polymer composition, which were compression molded using the following conditions: First, the pellets are melted at 120 °C for 1 minute at a pressure of 61 N/cm ² . Then the temperature is increased to 180 °C at a rate of 18 K/min and at the same time the pressure is increased to 614 N/cm ² . The temperature is maintained at 180°C for 20 minutes. The plates are then crosslinked by means of the peroxide present in the polymeric composition. The total crosslinking time is 24 minutes, which includes the time to increase the temperature from 120 to 180°C. After the crosslinking of the crosslinked plates, that is, the crosslinked polymer composition according to the present invention and the comparative crosslinked polymer composition, is completed, it is cooled to room temperature with a cooling rate of 15 K/min still under pressure. The final thickness of the plates is 1.5 mm.

Gas Chromatography (GC) analysis protocol, i.e. method for GC analysis

GC (Plate) analysis protocol, i.e. the method for GC analysis

The content of volatile peroxide decomposition products, herein methane (CH4), is given in ppm (weight) and is determined by gas chromatography (GC) from a crosslinked sample of the polymer composition according to the present invention and of the comparative polymer composition. Said crosslinking has been carried out as described in the plate crosslinking method.

A sample specimen with a thickness of 1.5 mm and a weight of 1 g is cut from the center of the crosslinked plate, that is, the crosslinked polymer composition according to the present invention and the crosslinked comparative polymer composition, directly after you have completed the crosslinking step (ie, in the method for crosslinking the plate). The obtained sample is placed in a 120 mL headspace bottle with a Teflon-sealed crimped aluminum container and heat treated at 60°C for 1.5 hours to equilibrate any gaseous volatiles present in the sample. Next, 0.2 ml of the gas captured in the sample bottle is injected into the gas chromatograph, where it is analyzed for the presence and content of the volatiles, eg methane, to be measured. Duplicate samples are analyzed and the reported methane content value is an average of both analyses. The instrument used herein was an Agilent 7890A GC with an Al ² Oa/NA ² SO ⁴ column with dimensions of 0.53 mm x 50 m and a film thickness of 10 µm, supplied by Plot Ultimetal. Helium was used as carrier gas and FID detection was used.

Method for determining hot fit

Hot setting method for cross-linked plate samples

Hot set elongation, as well as permanent set, were determined on samples taken from crosslinked plates, ie, the crosslinked polymer composition according to the present invention and the comparative crosslinked polymer composition. Those properties were determined according to IEC 60811-507:2012. In the hot fit test, a weight of the tested material is fitted with a weight corresponding to 20 N/cm ² . First, the specimen is marked with reference lines. From the middle of the specimen, make two reference lines (one on each side). The distance between the two lines, L0 is 20 mm. That specimen is placed in an oven at 200°C with the weight corresponding to 20 N/cm ² and after 15 minutes, the hot set elongation is measured as follows. The distance between reference lines after 15 minutes at 200 °C is called L1 and is measured. Then, the elongation after 15 minutes is calculated as follows: hot-setting elongation (%) = ((L1*100)/L0)-100. Subsequently, the weight is removed and the sample is allowed to rest for 5 minutes at 200 °C. The sample is then removed from the oven and cooled to room temperature. After cooling, the distance L2 between the 2 reference lines is measured and the permanent set is calculated as follows: permanent set (%) = (L2*100)/L0)-100.

Crosslinked plates were prepared as described in Preparation of crosslinked plate, i.e. method for crosslinking the plate, and weighted specimens were prepared from a 1.5 mm thick crosslinked plate according to ISO 527-2/ 5A:2012.

experimental part

examples

Polyethylene

The polyethylenes are all low density polyethylenes polymerized in a high pressure continuous tubular reactor. Inventive Example 1 (Polymer 1: Poly(ethylene-co-1,7-octadiene) polymer with 1.36 vinyl groups/1000 carbon atoms (C), Density = 922.4 kg/m ³ , MFR2 = 1, 13 g/10 mm), i.e. polyethylene of the polymer composition according to the present invention

The recycled CTA ethylene was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intercooling to reach an initial reaction pressure of about 2800 bar. performance total compressor was about 30 tons/hour. In the compressor area approximately 0.3 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 43 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 1 0.13 g/10 min. Here also 1,7-octadiene was added to the reactor in an amount of 132 kg/h. The compressed mixture was heated to 155°C in a preheat section of a front-fed three-zone tubular reactor with an internal diameter of approximately 40 mm and a total length of 1200 meters. Just after the preheater, a mixture of commercially available peroxide radical initiators dissolved in isododecane was injected in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 279°C, after which it was cooled to about 206°C. The 2 and 3 subsequent maximum reaction temperatures were 272 °C and 245 °C, respectively, with intermediate cooling to 217 °C. The reaction mixture was depressurized through a pressure valve, cooled, and the resulting polymer 1 was separated from unreacted gas.

Inventive example 2 (polymer 2: Poly(ethylene-co-1,7-octadiene) polymer with 0.89 vinyl groups/1000 C, Density = 923.7 kg/m ³ , MFR2 = 0.92 g/10 min ), i.e. polyethylene of the polymeric composition according to the present invention

The recycled CTA ethylene was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intercooling to reach an initial reaction pressure of about 2800 bar. The total throughput of the compressor was approximately 30 tons/hour. In the compressor area approximately 3.8 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added as chain transfer agents to maintain an MFR2 of 0.92 g/10 min. Here also 1,7-octadiene was added to the reactor in an amount of 89 kg/h. The compressed mixture was heated to 162°C in a preheat section of a front-fed three-zone tubular reactor with an internal diameter of approximately 40 mm and a total length of 1200 meters. Just after the preheater, a mixture of commercially available peroxide radical initiators dissolved in isododecane was injected in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 286°C, after which it was cooled to about 231°C. The 2 and 3 subsequent maximum reaction temperatures were 274 °C and 248 °C, respectively, with intermediate cooling to 222 °C. The reaction mixture was depressurized through a pressure valve, cooled, and the resulting polymer 2 was separated from unreacted gas.

Inventive example 3 (polymer 3: Poly(ethylene-co-1,7-octadiene) polymer with 1.34 vinyl groups/1000 C, Density = 924.9 kg/m ³ , MFR2 = 1.46 g/10 min ), i.e. polyethylene of the polymeric composition according to the present invention

The recycled CTA ethylene was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intercooling to reach an initial reaction pressure of about 2800 bar. The total throughput of the compressor was approximately 30 tons/hour. In the compressor area approximately 3.9 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added as chain transfer agents to maintain an MFR2 of 1.46 g/10 min. Here also 1,7-octadiene was added to the reactor in an amount of 148 kg/h. The compressed mixture was heated to 159°C in a preheat section of a front-fed three-zone tubular reactor with an internal diameter of approximately 40 mm and a total length of 1200 meters. Just after the preheater, a mixture of commercially available peroxide radical initiators dissolved in isododecane was injected in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 273°C, after which it was cooled to about 207°C. The 2 and 3 subsequent maximum reaction temperatures were 257 °C and 226 °C, respectively, with intermediate cooling to 209 °C. The reaction mixture was depressurized via a pressure valve, cooled, and the resulting polymer 3 was separated from unreacted gas.

Inventive example 4 (polymer 4: Poly(ethylene-co-1,7-octadiene) polymer with 0.94 vinyl groups/1000 C, Density = 922.3 kg/m ³ , MFR2 = 1.91 g/10 min ), i.e. polyethylene of the polymeric composition according to the present invention

The recycled CTA ethylene was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intercooling to reach an initial reaction pressure of about 2900 bar. The total throughput of the compressor was approximately 30 tons/hour. In the compressor area approximately 0.4 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 117 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 1 .91 g/10 min. Here also 1,7-octadiene was added to the reactor in an amount of 77 kg/h. The compressed mixture was heated to 162°C in a preheat section of a front-fed three-zone tubular reactor with an internal diameter of approximately 40 mm and a total length of 1200 meters. Just after the preheater, a mixture of commercially available peroxide radical initiators dissolved in isododecane was injected in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 267°C, after which it was cooled to about 205°C. The 2 and 3 subsequent maximum reaction temperatures were 260 °C and 237 °C, respectively, with intermediate cooling to 213 °C. The reaction mixture was depressurized through a pressure valve, cooled, and the resulting polymer 4 was separated from unreacted gas.

Comparative Example 1 (Polymer 5: Poly(ethylene-co-1,7-octadiene) polymer with 0.82 vinyl groups/1000 C, Density = not measured kg/m ³ , MFR2 = 2.1 g/10 min) , that is, polyethylene of comparative polymeric composition

The purified ethylene was liquefied by compression and cooling to a pressure of 90 bar and a temperature of -30 °C and divided into two equal streams of approximately 14 tons/hour each. CTA (methyl ethyl ketone ( ^m E ^k )), air, and a commercial peroxide radical initiator dissolved in solvent were added to the two liquid ethylene streams in individual amounts. 1,7-octadiene was added to the reactor as a comonomer in an amount of 190 kg/h. The two mixes were pumped separately through a matrix of 4 intensifiers to reach pressures of 2200-2300 bar and outlet temperatures of around 40°C. These two streams were fed respectively to the front (zone 1) (50%) and to the side (zone 2) (50%) of a split-feed two-zone tubular reactor. The internal diameters and lengths of the two reactor zones were 32 mm and 200 m for zone 1 and 38 mm and 400 m for zone 2. MEK was added at 115 kg/h to the front stream to maintain an MFR2 of about 2.1 g/10 min. The front feed stream passed through a heating section to reach a temperature sufficient for the exothermic polymerization reaction to begin. The reaction reached maximum temperatures of 253 °C and 290 °C in the first and second zones, respectively. The side feed stream cooled the reaction to a second zone initiation temperature of 165°C. A solution of air and peroxide was added to the two streams in amounts sufficient to reach the maximum target temperatures. The reaction mixture was depressurized via a product valve, cooled and the polymer separated from unreacted gas. The polymer obtained had vinyl groups in an amount of 0.82/1000 C and MFR2=2.1 g/10 min.

Comparative Example 2 (Polymer 6: Poly(ethylene-co-1,7-octadiene) polymer with 0.86 vinyl groups/1000 C, Density = not measured kg/m ³ , MFR 2 = 3.1 g/10 min) , that is, polyethylene of comparative polymeric composition

The recycled CTA ethylene was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intercooling to reach an initial reaction pressure of about 3000 bar. The total throughput of the compressor was approximately 30 tons/hour. In the compressor area, approximately 121 kg of propylene/hour were added as chain transfer agents to maintain an MFR2 of 3.1 g/10 min. Here also 1,7-octadiene was added to the reactor in an amount of 57 kg/h. The compressed mixture was heated to 165 °C in a preheat section of a front-fed three-zone tubular reactor with an internal diameter of approximately 40 mm and a total length of 1200 meters. Just after the preheater, a mixture of commercially available peroxide radical initiators dissolved in isododecane was injected in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 283°C, after which it was cooled to about 225°C. The 2 and 3 subsequent maximum reaction temperatures were 283 °C and 267 °C, respectively, with intermediate cooling to 235 °C. The reaction mixture was depressurized via a pressure valve, cooled and the polymer separated from unreacted gas.

Comparative Example 3 (Polymer 7: Poly(ethylene-co-1,7-octadiene) polymer with 0.77 vinyl groups/1000 C, Density = 922.1 kg/m ³ , MFR2 = 1.82 g/10 min ), that is, polyethylene of comparative polymeric composition

The recycled CTA ethylene was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intercooling to reach an initial reaction pressure of about 2900 bar. The total throughput of the compressor was approximately 30 tons/hour. In the compressor area approximately 0.8 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 123 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 1 .82g/10 min. Here also 1,7-octadiene was added to the reactor in an amount of 55 kg/h. The compressed mixture was heated to 163°C in a preheat section of a front-fed three-zone tubular reactor with an internal diameter of approximately 40 mm and a total length of 1200 meters. Just after the preheater, a mixture of commercially available peroxide radical initiators dissolved in isododecane was injected in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 274°C, after which it was cooled to about 204°C. The 2 and 3 subsequent maximum reaction temperatures were 261 °C and 244 °C, respectively, with intermediate cooling to 216 °C. The reaction mixture was depressurized via a pressure valve, cooled and the polymer separated from unreacted gas.

Comparative Example 4 (Polymer 8: Poly(ethylene-co-1,7-octadiene) polymer with 0.58 vinyl groups/1000 C, Density = 922.1 kg/m ³ , MFR2 = 1.75 g/10 min ), that is, polyethylene of comparative polymeric composition

The recycled CTA ethylene was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intercooling to reach an initial reaction pressure of about 2900 bar. The total throughput of the compressor was approximately 30 tons/hour. In the compressor area approximately 1.6 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 123 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 1 .75 g/10 min. Here also 1,7-octadiene was added to the reactor in an amount of 34 kg/h. The compressed mixture was heated to 164 °C in a preheat section of a front-fed three-zone tubular reactor with an internal diameter of approximately 40 mm and a total length of 1200 meters. Just after the preheater, a mixture of commercially available peroxide radical initiators dissolved in isododecane was injected in an amount sufficient for the exothermic polymerization reaction to reach maximum temperatures of about 276 °C, after which it was cooled to about 200 °C. The 2 and 3 subsequent maximum reaction temperatures were 266 °C and 251 °C, respectively, with intermediate cooling to 219 °C. The reaction mixture was depressurized via a pressure valve, cooled and the polymer separated from unreacted gas. Comparative Example 5 (Polymer 9: Poly(ethylene-co-1,7-octadiene) polymer with 0.71 vinyl groups/1000 C, Density = 922.3 kg/m3, MFR2 = 0.68 g/10 min) ie, polyethylene of comparative polymeric composition The recycled CTA ethylene was compressed in a 5-stage pre-compressor and a 2-stage hyper-compressor with intermediate cooling to reach an initial reaction pressure of approximately 2900 bar. The total throughput of the compressor was approximately 30 tons/hour. In the compressor area approximately 1.2 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 87 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 0 .68g/10 min. Here also 1,7-octadiene was added to the reactor in an amount of 56 kg/h. The compressed mixture was heated to 164°C in a preheat section of a front-fed three-zone tubular reactor with an internal diameter of approximately 40 mm and a total length of 1200 meters. Just after the preheater, a mixture of commercially available peroxide radical initiators dissolved in isododecane was injected in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 277°C, after which it was cooled to about 206°C. The 2 and 3 subsequent maximum reaction temperatures were 270 °C and 249 °C, respectively, with intermediate cooling to 217 °C. The reaction mixture was depressurized via a pressure valve, cooled and the polymer separated from unreacted gas. polymeric composition

The formulations, that is, the polymer composition of the present invention, using the polyethylene, as described herein, a crosslinking agent and no antioxidant, and also comparative examples, have been prepared on a laboratory scale and compared , see Table 1. The crosslinking agent was added to the polyethylene by distributing the crosslinking agent (the crosslinking agent is in liquid form) at 70°C over the polyethylene granules. The wet granules were kept at 80°C until dry. The amount of crosslinking agent, e.g. peroxide, e.g. DCP, was selected for each base resin so as to achieve approximately the same degree of crosslinking as measured by the hot setting method of determination (with a load of 20N /cm2).

For hot-setting and methane measurements, 1.5-mm-thick plates were compression molded and crosslinked at 180 °C as described in the determination method under "preparation of crosslinked plates, i.e. method for crosslinking plates". Methane was measured directly after crosslinking in 2 samples, as described in the determination method in the "GC Analysis Protocol (Plate), i.e. Method for GC Analysis" and the reported value is an average. of the 2 measurements. Hot setting was measured on 3 samples at 200 °C with a load of 20 N/cm2 as described in the determination method in "Hot setting method for samples of a cross-linked plate".

Table 1

The examples surprisingly show that the polymeric composition of the present invention, obtained from polyethylene, reaches excellent levels of crosslinking (< 200 ppm of methane. All comparative examples form more than 200 ppm of methane when crosslinked at a technically equivalent level). Therefore, the polymer compositions of the present invention, wherein the polymer composition contains a total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms and comprises a crosslinking agent in an amount that is Z wt. , are particularly suitable for end-use applications where there is a need for a system that combines a highly cross-linked system with the simultaneous formation of low-volatile decomposition products, typically methane.Therefore, a highly cross-linked system is surprisingly achieved even when using a comparatively small amount of cross-linking agent, e.g. For example, peroxide, eg, DCP, according to the present invention in the polymer composition containing a total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms. Thus, with a comparatively low amount of DCP, i.e. the crosslinker in an amount of Z < Z2, where Z2 is 0.60, surprisingly good levels of crosslinking as measured by hot setting (< 100% hot set elongation) by the polymer compositions of the present invention. In contrast, comparative polymer compositions, which contain a lower total amount of vinyl groups, need more than 0.6% by weight of the crosslinking agent, here DCP, to achieve sufficient levels of crosslinking to lead to the formation of products. volatile decomposition, usually methane.

Claims (23)

1. A polymeric composition comprising a polyethylene and a crosslinking agent, characterized in that the polymeric composition contains a total amount of vinyl groups that is B vinyl groups per 1000 carbon atoms, and B i < B, in where B i is 0.88, when measured before crosslinking according to method A ST M D6248-98; and in that the crosslinking agent is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymeric composition, and Z < Z ² , where Z ² is 0.60 . 2. A polymeric composition according to claim 1, wherein the polyethylene is unsaturated or saturated. 3. A polymeric composition according to any of the preceding claims, wherein the polymeric composition is crosslinked and has a hot-setting elongation, with a load of 20 N/cm 2, which is less than 175%, when measured by the hot-fit determination method. 4. A polymeric composition according to any of the preceding claims, wherein the polyethylene is an unsaturated L D P E polymer. 5. A polymeric composition according to any of the preceding claims, wherein the polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer and with zero, one or more other comonomers and wherein said total amount of vinyl groups (B) present in the polymeric composition includes vinyl groups originating from at least said polyunsaturated comonomer, eg, diene. 6. A polymeric composition according to any of the preceding claims, wherein the polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer, wherein the polyunsaturated comonomer is a linear carbon chain with at least 8 atoms carbon atoms and at least 4 carbon atoms between the doubles in nonconjugated bonds, of which at least one is terminal, for example, nonconjugated diene C to ^C14 , for example, selected from 1,7-octadiene , 1,9-decadiene, 1,11-dodecadiene, 1,13-tetrad ecadien or mixtures thereof. 7. A polymeric composition according to any of the preceding claims, wherein the polyethylene is a copolymer of ethylene and 1,7-octadiene. 8. A polymeric composition according to any of the preceding claims, wherein the polyethylene is a homopolymer or copolymer of low density polyethylene (LD P E ), for example, a copolymer of L D P E of ethylene with one or more comonom er (s) polyunsaturated and with zero, one or more comonomer(s). 9. A polymeric composition according to any of the preceding claims, wherein the polymeric composition has, before crosslinking, a melt flow index (M FR ² ) at a load of 2.16 kg and at 190 ° C, determined according to ISO method 1133-1:2011, where M FR ² is A g /10 min and A < A ² , where A ² is 2.5 or 2 or 1.7. 10. A polymeric composition according to any of the preceding claims, wherein said polyethylene, before crosslinking: has a complex viscosity (r|*) at 0.05 rad/sec, which is XP as, and X ¹ < X < X ² , where X1 is 7600 and ^X2 is 30000, and a complex v iscosity (r|*) at 300 rad/sec, which is YP as, and Y ¹ < Y < Y ² , where Y ¹ is 5 and Y ² is 380, both com plex v iscosities plexes (r|*) are determined according to the ISO 6721-1 method on stabilized polyethylene samples. 11. A polymeric composition according to any of the preceding claims, wherein B ¹ is 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25 or 1.30, and/or Z ² is 0.48 or 0.46. 12. A polymeric composition according to any of the preceding claims, wherein B < B ² and B ² is 3.0 and Z ¹ < Z < Z ² , where Z ¹ is 0.01. 13. A polymeric composition according to any of the preceding claims, wherein the polyethylene contains a total amount of vinyl groups that is P vinyl groups per 1000 carbon atoms, where P ¹ < P < P ² and P ¹ is 0 .89 and P2 is 3.0, preferably where P1 is ^0.90 and ^P2 is ^1.5 . 14. A polymeric composition according to any of the preceding claims, wherein the polymeric composition simultaneously complies with the following: ^P1 < P < ^P2 where ^P1 is 0.89 and ^P2 is 3.0; Z ¹ < Z < Z ² where Z ¹ is 0.15 and Z ² is 0.60; Y A ¹ < A < A ² where A ¹ is 0.15 and A ² is 3.0. 15. A polymeric composition according to any of the preceding claims, wherein the polymeric composition simultaneously complies with the following: P i < P < P ² where P i is 0.9 and P ² is 1 ,5 ; Z i < Z < Z ² where Z i is 0.25 and Z ² is 0.50; Y A i < A < A ² where A i is 0.60 and A ² is 2.5. 16. A polymeric composition according to any preceding claim, wherein the crosslinking agent comprises peroxide. 17. An article obtained from a process comprising the use of a polymeric composition according to any of claims i to i6, wherein the article is, for example, a cable. 18. An article according to claim i7, wherein the article comprises layer(s), for example, insulating layer(s), which is (are) obtained from a polymeric composition according to any of the claims i to i6, wherein the article is, for example, a cable. 19. An article according to claim i7 or i8 which is a power cable. 20. A process for producing a polymeric composition according to any of claims i to i7, the process comprises mixing the polyethylene with the crosslinking agent. 21. A process for producing an article according to any of claims i7 to i9, which process comprises the use of a polymeric composition according to any of claims i to i6. 22. A process according to claim 2 i, wherein said article is a power cable and wherein said process comprises the following steps: ao) blending by melting a polymeric composition as defined in any of claims i to i6, optionally together with other components; a) apply the mixture by fusion obtained in step a ⁰ ) on a conductor to form at least one layer. 23. A process according to claim 22, wherein said article is a crosslinked power cable and wherein said process further comprises the following step: b) crosslinking at least one layer of cable obtained from step a).